Manufacture of lubricating oil



Feb. 8, 1949. F. c. TOETTCHER 2,461,454

MANUFACTURE OF LUBRICATING OIL Filed May- 4, 1945 I ////As 1000 00 I l I l l I o 20 40 so so BOTTOMS 664cm): /0% Cars.

IPA-".0 C 75:270/52 BYVWW;

ATTOIPA/E).

Patented Feb. 8, 1949 MANUFACTURE OF LUBRICATING Fred C. Toettcher, Fishkill, N. Y., assignor to The Texas Company, New York, N. Y., a corporation of Delaware Application May 4, 1945, Serial No. 592,055

2 Claims. 7 1

This invention relates to the catalytic treatment of hydrocarbon oils to produce lubricating oils highly resistant to oxidation. The invention is concerned with certain improvements in the treatment of lubricating stocks to effect improvement in oxidation stability and to produce oils of highly stable character adapted for turbine oils, lubricating oils for internal combustion engines and the like.

In accordance with the invention the oil is fractionated lntoa plurality of fractions and these fractions or a. selected fraction or selected fractions thereof are subjected to catalytic treatment to effect improvement in oxidation stability. The invention is based on the discovery that when lubricating oil is subjected to the catalytic treatment the extent of improvement in oxidation stability is generally greater in the higher boiling or higher viscosity components of the treated product and that when an oil stock is fractionated into a plurality of cuts and the several cuts subjected to separate catalytic treatments of identical severity greater improvement in oxidation stability is produced on the higher boiling or higher viscosity fractions.

For the purpose of fully disclosing the invention reference is had to the accompanying drawing which is a graph showing a comparison of the treatment of the entire stock with the treatment of separated fractions thereof.

In order to show the advantages of the invention a comparison is made between the catalytic treatment of the entire stock and the treatment of certain fractions thereof. A naphthenic pale oil stock of 500/ 100 F. Saybolt Universal viscosity was subjected to fractionation under vacuum distillation to produce 10% distillate cuts and a residual or bottoms fraction. Certain of these fractions including the 20-30%, the 40-50%, the 60-70%, the 80-90% fractions of the distillate and the undistilled bottoms were each separately treated with Super Filtrol (10% by weight) at 600 F. for a period of one and one-half hours. In the drawing the 10% fractions and the bottoms fraction are plotted as abscissa and the-oxidation stability as determined by the A. S. T. M. Turbine Oil Oxidation test is plotted as ordinates -(the test life is expressed as the munber of hours required for the oil to reach a neutralization number of 2). Curve A or the dots thereon indicate the oxidation test life of the several products obtained in the catalytic treatment of the several fractions of the pale oil. Each of the catalytically treated products was subjected to distillation to strip off a light fraction constituting 2 10% of the treated productt Curve B or the points thereon (solid triangles) indicate the oxidation test life of the stripped products. It will be observed that the stripped products have con siderably longer test life than the unstripped products. The entire pale oil stock was also subjected to catalytic treatment under the same conditions as were applied to the several fractions and the resultant product was fractionated to obtain 10% distillate cuts and a residual 0r bottoms fraction. Curve C or the points thereon (open triangles) represent the oxidation test life of these fractions.

It is evident from the data that considerably longer oxidation test life can be obtained by the catalytic treatment of the fractions than by treat,- ing the whole oil stock in one operation. Accordingly in practicing the invention the lubricating stock is fractionated into a plurality of cuts and each of these cuts or selected cuts are subjected to the catalytic cracking. The several products, preferably after stripping off the lighter fractions, are then blended to produce a high quality lubricating oil. The fractionation of the lubricating oil to obtain the fractions for treatment and the stripping of the treated fractions are preferably conducted under vacuum distillation so" as to avoid thermal cracking. In the stripping of the treated products the distillation may be conducted to an extent sufficient to reduce each treated fraction to the same viscosity as thatof the fraction before the catalytictreatment or each treated fraction may be stripped to yield a product of even higher viscosity than such fraction.

The catalysts which are adapted for the practice of the invention comprise certain composites of silica and alumina and include generally the activable clays particularly the non-swellingacid treated montmorillonite or bentcnitic clays. Industrial clays which have been found particularly effective are Super Filtrol and Lena clay each of which is a nonswelling, acid treated bentonitic clay. 1

In the treatment to effect the increase in oxlda tion stability the lubricating stock is contacted with the catalyst in pulverulent, comminuted form at temperatures upwards of 600 F. In order to obtain the maximum improvement in oxida- 56 It is desirable that the treatment he conducted I with the oil essentially in the liquid phase and consequently the temperature should be kept below the critical temperature of the stock being treated. Moreover, as the temperature is in creased there is greater danger of having thermal cracking at the expense of the desired selective catalytic conversion. Consequently in order to avoid cracking} intol'low boiling: component's, z-such as gasolineythe upper limit of the temperature of treatment for the lubricating oil stocks is about 750 and generally a temperature of about 650 725 F. is the most satisfactory. .For-.-the .most efiicctive operation the quantity of catalyst used should be about 8-10 by weight oi=the oil: treated such, for 'example, as distillation. While it is difilcuittodetermine: the exact natureof the reactionsain thetreatinenh'it appears thatfin general there some increase in both aromaticity and paraflinicity apparently at the expense of :naphthenic rings. I *In accordance with the-invention the lubricating'o'il: isfractionatedinto a plurality of cuts alld'lthe several "fractions or selected fractions thereof, especially the higher viscosity fractions,

are separately subjected to the catalytic conversiontc efiectr increase in oxidation stability.

1115036 method of operation the less viscous fractionsmaybesubjected-to more drastic conversion conditions than the higher viscosity fractions. The severahtreated products are stripped to .pro- ;ducezproducts of the same or higher viscosity as that ofzthe fractionsbefore the treatment and .the stripped products are'blended-with the untreated-fractionsto'produce a composite product or qdeslre'd viscosity and oxidation stability. In

one'method of operation the lubricating stock is fractionated tokproduce a single fraction for.

the invention, lowerboiling fractions obtained in the :fractionation of the 'catalytically treated fproducts'more particularly the fractions of lower =viscosit'yrthan that'ofthe-charge to the catalytic treating operation, may be recycled to the catalytic itreating zone so that the'lower viscosity :constituents may thus 'be-subiected to 'furth'er :tconversionrfor increase in oxidation stability.

*The'zinvention is adapted for the treatment-of either rawlubricatingstocks or refined stocks in "sofifar eas efiecting the improvement in oxidation stability-is concerned. However in the 'treatmellti'flf oils for certain purposesas in the profduction-of'turbineoils which are'required to have a high-"oxidation-stability.and'also must be re- .sistantttogemulsion or'mustrea'dily separate from emulsions which-may ibe -produced' in'- the: use a:

4 the oil, it is necessary that the catalytic treatment be applied after the oil has been subjected to the refining treatment, such as acid treatment and solvent refining, since if the oil, after being given the catalytic treatment, be subjected to after-treatments, such as sulfuric acid treating, solvent refining, caustic Washing and similar treatments, whilethe emulsion characteristics of the oil maybe improvedthe after-treating tends to greatly reduce the oxidation stability imparted to the oil by the catalytic treatment. Accordingly in-the -productionof an oil which will have both high oxidation stability and good emulsion char- -a'cteristics, it iscritical that the catalytic treat- =ment for improvement in oxidation stability fOllOW the other refining treatments. The catalyticallytreatedoil or the blend of the catalytically and untreated oil may further be subjected to filtration through clay or fullers earth at modvarious types of apparatus.

crate temperature for improvement in color without impairing its quality for turbine oils.

In practicing the invention the mixture ofoil and catalysts may be subjected to .reactiondn A preferred opera tion is to pass the mixture oi'oil and comminuted catalyst through a carefully regulated heating 'coil and to either quench the efliu'ent orito pass it through a cooler adapted for rapid coolingso as to thus accurately control thettimeof reaction. Thecatalyst should be. addedtotheoii with the oilat normal temperature or at least after only moderate preheating so, asto eliminate the effect of any strictly thermal reaction. The cooled oil is passed to a distilling or fractionating zone for removing the lighter fractions. These lighter fractions may be removed from the system or recycled to the heating coil. A plurality of heating and fractionatingunits maybe employed so as to simultaneously treat thevarious fractions.

Although a preferred embodiment of the inven tion has been described herein, it Willibe under stood that various changes and modifications may be made thereimwhile securing to agreater or less extent some or all of the'benefits of the invention, without departing from the spirit and scopethereof.

I claim:

1. The method of improving the oxidationstability oflubricating oil of the pale oil type that comprises separating from the lubricating oil a minor fraction constituting the higher boiling portion thereof, treating the minor fraction with activated'clay at a temperature'upwards o'f 600 F. and not in excess of about 750 Fiwith a reaction time of the order of -2 hours to thereby effect reactions involving an increase in aromaticity and formation of structures which inhibit oxidation, distillingofi lower boiling constituents from the treated fraction to'thereby concentrate the oxidation inhibiting constituents-and blending the resultant stripped product with the untreatedmajor portion of thelubricatingoil-to produces; blended product of increasedoxidation stability.

' 2; The method of improving the oxidation stability of lubricating oil of-the pale .oil type that comprises separating from the lubricating oil :a higher boiling fraction thereof constituting about 10-25% of the oil, treating said fraction with activated clay at a temperature-upwards-of 600 F. and not in excess of about 750 F4Wlth2, reaction time of the order of hours to t-hereby effect reactions involving an increase in arcmatici'ty and formation ofstructures which {inhibit "oxidation, 1 distilling ofi lower boilirig con-- REFERENCES CITED The following references are of record the file of this patent:

UNITED STATES PATENTS Number Name Date 1,547,682 Puitzm'an July 28, 1925 1,655,175 Benjamin Jan. 3, 1928 Number :6 Name Date Johnston June 24, 1930 jlsom et al Dec. 30,1930 vyvery et al July '7, 1931 ijStaiTord May 3, 1932 Darlington Oct. 25, 1932 Belden Feb. 21, 1933 Beiswenger Aug. 21, 1934 Tuttle Feb. 9, 1937 Brandt Nov. 19, 1940 Bray et a1 July 1, 1941 Schumacher et a1. Feb. 17, 1942 Evans et a1 Feb. 8, 1944 Lovell Feb. 15, 1944 Smith Aug. 29, 1944 Stratford et a1. May 6, 1947 Certificate of Correction Patent No. 2,461,454. February 8, 1949.

FRED G. TOETTOHER It is hereby certified that error appears in the printed specification of the above numbered patent requiring correctlon as follows:

Column 2, line 46, after the word comminuted insert or powdered;

THOMAS F. MURPHY,

Assistant Oommzm'oner of Patents. 

